We need a range of social media platforms that connect us in different ways.

Speaking at the Aspen Ideas Festival last week, co-founder of Internet community site Reddit, Alexis Ohanian, shared a joke that's popular on his site: "Facebook makes me hate the people I know, and Reddit makes me love the people I don't."
Given Facebook's $60 billion market capitalization and unchallenged position as the world's most-visited website, Ohanian's quip sounds like sour grapes. (Ohanian and his parters sold Reddit to Conde Nast in 2006 for an undisclosed sum, likely orders of magnitude smaller than Facebook's valuation.) But there's reason for Ohanian to imply a competition between a site used by 6 percent of American Internet users and one used by 67 percent, according to recent statistics by the Pew Internet and American Life Project.
Reddit, which calls itself "The Front Page of the Internet," is more influential in shaping Internet culture than its comparatively small reach would lead you to believe. Content featured on Reddit frequently "goes viral," spreading to other websites, including Facebook. As a result, it's become a popular destination for politicians and other public figures, including President Obama, to meet their online audiences, often through distributed interviews called AMAs -- Ask Me Anything.
There are reasons why Reddit makes Ohanian love total strangers. Reddit has a well-deserved, if eclectic, reputation for charitable giving. Redditors raised $700,000 to send a bullied senior citizen on a vacation, $4,000 to send to correspondent Helen Thomas after she asked White House spokesperson Dana Perino pointed questions about torture, and over $200,000 for World Vision, Doctors Without Borders and Islamic Relief in a competition between "sub-reddits" focused on Christianity, atheism, and Islam. And Reddit is emerging as a significant political force on issues that concern the Internet, serving as breeding ground for a massive protest against Internet registrar Go Daddy over the controversial SOPA/PIPA legislation and recently promoting "Take Back the Fourth" rallies to oppose NSA surveillance.
But the interesting piece of Ohanian's comment is the idea that Facebook and Reddit operate in radically different ways. For many Internet users, "social networks" are sites that build online links between people who already know each other offline. This was an idea exemplified in early social networks like Six Degrees (named after the six degrees of separation concept promoted by Stanley Milgram) and used in Facebook, Linked In, and Google Plus. When you join Facebook, the service mines your email inbox for friends, then asks questions about your education and work history to identify other possible contacts. Who you know on Facebook closely parallels who you know in the real world -- according to a Pew study, only 7 percent of Facebook friends are people a user knows only in an online context.
Because social networks like Facebook are all about who you know, they tend to be obsessed with authenticated identities. From its roots on elite college campuses, accepting only users with .edu email addresses, Facebook has had a "real name policy," which allows the site to remove the accounts of users who are using pseudonyms, arguing that online behavior is better when people are required to own their words. Google has followed suit, urging users to use real names on Google Plus and on YouTube. (These policies have raised questions from the human rights community, which points out that activists using online tools have valid reasons to conceal their identities, as do youth exploring sensitive questions around gender and sexuality.)
Reddit, by contrast, doesn't care who you are or who you know offline. Reddit names are unconnected to real-world identities and it's commonplace for users to create "throwaway" accounts to reveal sensitive information. In this sense, Reddit is more like the pre-social media Internet, when a New Yorker cartoonist could reasonably joke "On the Internet, no one knows you're a dog."
Identity isn't the only way Reddit has learned from early Internet culture. While Facebook is organized around your friends, replicating your offline social network, Reddit is organized around topics. This is a model that parallels Usenet, the Internet's ur-social network, a set of distributed message boards that served as a foundational influence on many builders of the contemporary commercial Web. While Facebook reconnects you with people you knew in elementary school or worked with years before, Reddit introduces you to strangers who share a common interest in photography, "Game of Thrones" or European politics.
Because Reddit connects strangers, it has certain advantages over Facebook, which connects friends. Ideas may spread more widely from Reddit than from Facebook despite a smaller pool of users. An idea shared between Facebook friends may peter out quickly as social networks reach saturation: an idea spread through friends who went to the same college may lose momentum when all alumni have heard about it. Reddit users are connected to many different communities, and an idea spread on Reddit's front page may go on to spread in thousands of different groups of friends on Facebook. This power to disseminate ideas to many different social subnets may explain why Reddit memes often go viral and why Reddit has emerged as a key node in online activism.
Reddit may also have an important role in increasing cognitive diversity online. Thinkers like Cass Sunstein and Eli Pariser are worried that the Internet makes it too easy to isolate ourselves in ideological echo chambers, listening only to those who agree with us. In my new book, Rewire, I argue that social networking tools threaten to isolate us not just in terms of ideology, but in terms of nationality and cultural identity, by heavily connecting us to friends and neighbors instead of helping us build new relationships. By organizing around topics, instead of around offline relationships, Reddit offers the possibility of introducing us to people outside our normal circles and creates a context for conversation.
This isn't to say that Reddit is better than Facebook, even in terms of increasing our cognitive diversity through exposing us to different points of view. If I use Facebook to stay in touch with my high school friends who are church-going Republicans, I may be getting more ideological diversity than in hanging out with secular progressives on the World Politics sub-reddit.
It's not that Ohanian is right and Zuckerberg is wrong. We need a range of social media platforms that connect us in different ways. It's fine to have social media that connects us with old friends, but we need tools that help us discover new people, as well. Tools that help us discover and fall in love with strangers may be the key to making sure that social media doesn't descend into an insular echo chamber where the voices of those we already know eventually drive us mad.